Coupling means

ABSTRACT

A coupling means for detachably coupling a working implement (1) to the operating arm of an excavating machine, said coupling means comprising an attachment means (25) supported by the operating-arm stick and operating cylinder and having a shaft (23) journalled horizontally at the stick, and a shaft (24) journalled on the operating cylinder, said coupling means also comprising an attachment means (20) supported by the implement (1) and comprising a coupling device (4, 5) and a locking device (21). According to the invention the attachment means (25) of the operating arm comprises two link arms (26, 27) journalled at the shafts (23, 24), each link arm having a free abutment portion (36) protruding as an extension of the link arm in backward direction from the shaft (24). The link arms (26, 27) and the implement attachment means (20) comprise counter members (39 and 16, 17) cooperating with each other under pressure, the locking device (11, 21) being arranged to exert pressure on the abutment portions (36) of the link arms (26, 27), thus moving the link arms (26, 27) in the direction of the coupling device (4, 5) through wedge and lever cooperation with said counter members (16, 17 and 39) and abutment portions (36) and pressing the operating arm attachment means (25) against the coupling device (4, 5) to produce a permanent, play-free joint between implement (1) and operating arm.

The present invention relates to a coupling means for detachablycoupling a working implement to the operating arm of an excavatingmachine, said implement having an upper surface facing the operatingarm, with a front edge facing the excavating machine.

Couplings of the type described above are known in a variety ofembodiments, see for instance U.S. Pat. Nos. 3,269,570 and 3,556,323,swedish publications Nos. 216 635 and 8003255-0, and German publicationsNo. 2 500 217. Although these can be called quick couplings and have thedesired features in this respect, they have a number of other featuresrendering them not entirely satisfactory. A common feature of many suchquick couplings is thus that, due to their solid construction, theyincrease the weight of the operating arm to such an extent that theweight of the implement itself must be correspondingly reduced in orderto fulfill the inspection standards. This results in an undesiredreduction in bucket volume. Further, the known couplings have attachmentmembers of such a construction that they entail a considerable overallheight or distance between operating arm and bucket, i.e. between theattachment members. Particularly the attachment member on the operatingarm forms a substantial, solid, rigid intermediate piece between theoperating arm and the attachment point of the bucket, this greatlycontributing to said weight increase. Since the construction thereforerequires more than two pivot centres it does not offer optimalconditions for the force transmission between operating arm andimplement via the coupling. Poor breaking force is thus obtained in thebucket or other implement and the coupling is subjected to considerablestress. The bucket has a fixed geometry initially, i.e. without thequick coupling. However, due to the size of the known couplings, thisgeometry is altered in an undesired manner. To compensate for thedeteriorated breaking force, it has been necessary to place the breakingshaft, i.e. the operating cylinder shaft, further from the stick shaft,but this instead results in decreased torque, thus reducing thepivotable distance of the bucket and deteriorating inwardly andoutwardly pivoting movements of the bucket. Redesigning of the bucketusually results in the omission of the dome at the top which is used forforce transmission between stick and bucket and to make the bucket aslight and strong as possible. Known couplings cannot withstand diagonalbreaking movements in vertical direction and breaking forces of thebucket unless the intermediate piece of the coupling which is thusrigid, is made relatively strong and bulky, resulting in increasedweight. The couplings are therefore butt with respect to such diagonalbreaking movements of the bucket and all forces must pass through thecoupling. This becomes fatigued and will rupture if the forces becometoo great. At such diagonal breaking movements the load is reduced ontwo diagonal contact points in horizontal direction and correspondinglyincreased on two other of the four diagonal contact points at which thecoupling is joined to the bucket, whereupon a gap occurs at the twofirst contact points.

The object of the present invention is to substantially reduce theproblems mentioned above, and to provide in many respects a considerablyimproved coupling for excavating machine implements such as buckets,enabling the bucket to be simply and quickly mounted and dismounted fromthe operating arm of the excavating machine and which is entirely freefrom any bulky intermediate piece providing overall height between thelower shaft of the operating arm and the attachment point on the bucket.The coupling thus becomes correspondingly lighter and the volume orcapacity of the bucket can be maintained as desired. The elimination ofsuch an intermediate piece which increases the overall height of thecoupling results in simplified construction as well as a considerablesaving in material, with resultant financial advantages. The couplingaccording to the invention also offers improved conditions for the forcetransmission between bucket and operating arm, as well as making anyalteration of the bucket geometry unnecessary. The coupling can alsoeasily withstand diagonal breaking movements from the bucket despite thefact that it is more than considerably lighter than known couplings.

The invention provides a coupling means comprising an attachment meanssupported by the operating-arm stick and operating cylinder andcomprising a shaft journalled horizontally at the stick, and also ashaft horizontally journalled directly or indirectly on the operatingcylinder, said shafts being parallel and spaced a predetermined distancefrom each other, said coupling means also comprising an attachment meanssupported by the implement and comprising a coupling device and alocking device, by means of which coupling and locking devices theattachment means of the implement is arranged to be detachably coupledto the attachment means of said operating arm, said attachment means ofthe operating arm comprising a link means in the form of two link armsjournalled at the end of said shafts by means of shaft supports includedin the link arms, each link arm having a free abutment portionprotruding as an extension of the link arms in backward direction fromthe operating cylinder shaft on the side of the operating cylinder shaftfacing away from the stick shaft, said link arms and implementattachment means comprising counter members cooperating with each otherunder pressure, and said locking device being arranged to exert pressureon the abutment portions of the link arms, thus moving the link arms inthe direction of the coupling device through wedge and lever cooperationwith said counter members and abutment portions and pressing theoperating arm attachment means against the coupling device to produce apermanent, play-free joint between said implement and operating arm.There is thus no rigid connections between the link arms and they cantherefore move in their respective vertical planes upon vertical pointstresses from the bucket or other implement. The link arm arrangementalso eliminates the need for an intermediate piece which would increasethe overall height of the coupling means.

A preferred embodiment of the invention is characterised in that theattachment means of the operating arm is arranged to be pressed againstthe coupling device by means of the link arms which are thus in directcontact with the coupling device. In this case the link arms areprovided at the ends facing away from the abutment portions with freeexternal support surfaces of predetermined shape, the coupling devicebeing provided with free support surfaces of the same predeterminedshape as the free support surfaces of the link arms for intimate surfacecooperation therewith, whereupon the pressure from the locking devicepropagates through the links and is transmitted to the coupling devicevia said free support surfaces and that the distance for transmission offorces generated between implement and operating arm via the stick shaftand the coupling device of the implement are limited to a minimumequivalent to the wall thickness at said free external support surfaces,measured between these support surfaces and the opposing inner surfaceabutting the stick shaft. Besides the advantages mentioned above, such acoupling enables the operating arm attachment means to be easilyadjusted to several different makes of excavating machines withoutaltering the bucket attachment means. This means that one and the samebucket provided with an attachment means according to the invention canbe quick-coupled to several different makes of excavating machines.

According to another embodiment of the invention, the stick shaft isarranged to be brought into direct engagement with said coupling deviceon the implement attachment means, the locking device being arranged toexert a pressure on the link arms, thus pressing the stick shaftdirectly against the coupling device to produce a permanent play-freejoint between implement and operating arm. More specifically, each linkarm is journalled on the shaft by means of a mounting plate providedwith a hole and located outside the shaft, and is provided with anarc-shaped counter member which by means of a concave support surfaceabuts directly against the shaft which is thus pressed against thecoupling device, the hole in the mounting plate being sufficiently largein relation to the diameter of the shaft pin to permit this transmissionof pressure to the coupling device. This offers the advantage that theforces between stick and implement pass directly through the stick shaftto the coupling device, thus eliminating yet another point of play.

Additional advantages and objects will be apparent from the followingdescription and claims.

The invention will be described further in the following, with referenceto the accompanying drawings.

FIG. 1 shows schematically a bucket seen from the side provided on itsupper side with parts of the attachment means of a coupling meansaccording to one embodiment of the invention.

FIG. 2 shows an attachment means, seen from below, intended to cooperatewith the attachment means part shown in FIG. 1 and forming a portion ofsaid embodiment of the coupling means according to the invention.

FIG. 3 shows the bucket according to FIG. 1, seen from above.

FIG. 4 shows a link arm seen from above, which is included in theattachment means according to FIG. 2.

FIG. 5 shows the two attachment means according to FIGS. 2 and 3connected together at the bucket.

FIG. 6 shows the coupling means according to FIG. 5, seen from above.

FIG. 7 shows a side view of a locking pin included in the bucketattachment means.

FIG. 8 shows schematically from above a bucket with a coupling meansaccording to another embodiment of the invention.

FIG. 9 shows the bucket according to FIG. 8, and the bucket attachmentmeans of the coupling means.

FIG. 10 shows schematically parts of the coupling means according toFIG. 8, seen from the side.

FIGS. 11 and 12 show another embodiment of a quick coupling arrangementin which the stick shaft is in indirect engagement with the couplingdevice of the bucket. FIG. 13 shows a modification of the coupling meansof FIGS. 8 to 10.

With reference to FIG. 1 there is shown an implement in the form of abucket 1 for a excavating machine in which the bucket is provided on itsupper side 2, i.e. the side facing away from the digging edge 3, with anattachment means 20 (FIGS. 3 and 5) for a coupling means in the form ofa quick coupling according to the invention. This bucket attachmentmeans comprises a coupling device in the form of two hooks 4, 5, spacedfrom each other, which are welded to the upper side 2 at the front edge6 of the bucket opening 7. Each hook comprises an elongatesemi-cylindrical element 8, the elements being aligned with each otherand parallel to the front edge 6 of the bucket. The hook elements areopen towards the upper side of the bucket and form inwardly facing, i.e.facing away from the front edge 6, functional support surfaces 9 ofconcave or semi-cylindrical, predetermined shape for intimatecooperation with corresponding support surfaces on an attachment meanson the operating arm of the excavating machine, as will be describedbelow. The bucket attachment means 20 is provided with a locking devicecomprising a fixed, shackle-shaped part 11 which has a through-opening12 and aligned parallel to said support surfaces 9. The shackle 11 ispermanently secured to the bucket on the centre-line of the upper side.The opening 12 forms a flat, functional support surface 13 facing theupper side 2 of the bucket to cooperate with the corresponding supportsurface of a free tension pin 21 (see FIG. 5) as will be describedbelow, said tension pin constituting a detachable part of the lockingdevice. The locking device also includes a wedge support 14 (see FIG. 3)with a through-opening 15 aligned with the opening 12 of the shackle 11.The wedge support 14 may be shaped as an eye or a lug, as shown, or itmay consist of two erect fingers with the opening between them. Theparts 11, 14 of the locking device are thus secured to the upper side 2of the bucket and arranged at a predetermined distance from the hooks 4,5, in the vicinity of the rear edge 10 of the bucket.

The bucket attachment device 20 also comprises two shoulder-like countermembers 16, 17 welded to the upper side 2, which are aligned with thehooks 4, 5 and arranged between the lock shackle 11 and the hooks 4, 5in the vicinity of the lock shackle 11, i.e. at a considerable distancefrom the hooks 4, 5. Each counter member 16, 17 is provided with a flat,functional support surface 18, 18, these support surfaces lying in thesame plane and being inclined inwardly in the direction of the hooks 4,5 to cooperate with the corresponding support surfaces on the operatingarm attachment means, as will be explained in the following.

The operating arm of the excavating machine comprises a stick (notshown) and a hydraulic operating cylinder (not shown) arranged on thefront of the stick (facing away from the excavating machine), the stickbeing provided at its free end with a horizontal pin or shaft 23,pivotably carrying the bucket 1 and thus forming the centre ofoscillation of the bucket, while the hydraulic cylinder either directlyor indirectly via links is provided with a horizontally arranged pin orshaft 24 lying parallel to the stick shaft 23 and thus located in frontof this and joined to the bucket 1 to obtain a controlled swingingmovement of the bucket about the centre of the shaft 23.

Said shafts 23, 24 form parts of an attachment means 25 on the operatingarm, which also includes a link means in the form of two parallel linkarms 26, 27, each comprising a shaft support located at one end of thelink arm, in the form of a mounting plate 28 with a horizontal hole 20to receive the shaft end 30 of shaft 23 and a shaft support at apredetermined distance from said hole 29 in the form of a cylindricalsleeve 31 with a horizontal hole 32 to receive the shaft 24. Said shaftsupports may be arranged with (i.e. as shaft bearing means) or withoutturning of the shaft and may include bushings. Each link arm is alsoprovided or formed with an arc-shaped counter member 33 forming afunctional, concave support surface 34 extending transversely, i.e.axially (in relation to the shaft 23), having the same radius and beingarranged to abut the shaft 23, this also being provided with a functioncylindrical support surface 35, also arranged to abut said functionsupport surface 9 of the hooks 4, 5.

Each link arm comprises an abutment portion 36 exerting leverage whichprotrudes freely from the sleeves 31 in a backward direction from theshaft 24, i.e. in the direction of a backward extension of the linkarms, forming an obtuse angle with the waist or main portion 37 of thelink arm, located between the shafts 23, 24. On its upper side, facingaway from the bucket 1, the abutment portion is provided with afunctional, flat support surface 38, arranged to cooperate with acorresponding support surface of said free tension pin 21, as will bedescribed below.

Furthermore, each link arm is provided immediately below the sleeves 31with a counter member 39 designed with a functional, flat supportsurface 40 arranged to abut and cooperate in a wedge-like manner withsaid functional support surface 18, 18 of the counter member 16, 17 onthe bucket attachment means. Said functional support surfaces 18, 18; 40incline towards the hooks 4, 5 and have the same inclination. Thisinclination is such that in their extended planes the support surfacesof the counter members form an acute angle α with the support surfaces38 of the abutment portions. The angle α may be about 35°-85°,preferably 50°-60°, in order to achieve the required wedge-effect whenthe link arms are clamped between the fixed locking shackle 11 and thehooks 4, 5 via the counter member 16, 17 with the aid of the loosetension pin 21 of the locking device. The support surfaces 18, 18; 40are preferably inclined so that in extended plane they form an acuteangle β of from about 10° to about 65°, suitably 30°-60°, preferablyabout 45 °, with said centre plane C₁ -C₂. The inclination of thesupport surfaces 18, 18; 40 of the counter members 16, 17; 39, i.e. theangle β should not be too large, i.e. not above about 65°, as this mightcause unfavourable influence from the stroke of the hydraulic cylinder,on the stick shaft and the support surfaces at this part of the joint.

The mentioned tension pin 21, shown in more detail in FIG. 7 andconstituting the loose part of the locking device of the bucketattachment means, are elongate with rectangular cross-section increasingfrom substantially the middle in the direction of the rear part 41 ofthe tension pin, forming a wedge section 42 provided on the upper sideof the tension pin with a functional, flat support surface 44. The lowerside 47 of the tension pin forms a functional support surface 48. Thetension pin is also provided with a transverse, rectangular hole 49 inits front section 45, the hole 49 fitting a locking wedge 50 (FIG. 6).The inner edge 51 of the hole is located so far in that the lockingwedge does not come into contact with this edge once a final, play-freelocking position has been achieved, but only with the wedge support 14.The locking wedge is provided with a plurality of small apertures 52 sothat the wedge can be held in place by a peg 53 inserted in the hole 52nearest the tension pin once said locking position has been achieved.The inner support surface 13 of the locking shackle has the sameinclination as the support surface 44 of the tension pin 21 in order toachieve the desired wedge-effect.

The bucket is coupled extremely quickly and easily to the operating armof the excavating machine by means of the described attachment means.The first step is to adjust the operating arm so that the stick shaft 23is brought into direct engagement with the hooks 4, 5 of the bucket,after which the counter member 16, 17 of the bucket and the countermember 39 of the operating arm attachment means, by connection of thehydraulic cylinder, are brought into alignment with each other at saidsupport surfaces 18, 18; 40. In this starting position the abutmentportions 36 of the link arms 26, 27 are sufficiently far beneath thesupport surface 13 of the locking shackle 11 for the elongate tensionpin 21 to be passed without obstruction into the passage formed betweenthe support surfaces 13 and 38 with said abutment portions 36 in lightcontact with the lower side 47 of the tension pin. With the aid of atool, e.g. a sledge-hammer, the tension pin 21 is then driven into saidfixed locking shackle 11 until a play-free joint is obtained. Thelocking wedge 50 is then inserted into the hole 49 of the tension pin,hammered in as a wedge and locked in its final position with the peg 53.Dismantling is performed in an equally simple and quick manner in thereverse order. When the tension pin 21 is driven in a permanentwedge-force is produced between the abutment portions 36 of the linkarms and the locking shackle 11 of the bucket attachment means at thesurfaces 13, 44 and 38, 47 producing a leverage on abutment portions 36.This wedge-force is transmitted to the slidingly cooperating countermembers 16, 17; 39 so that support surfaces of the counter member 39slide down along the support surfaces 18, 18 of the counter member 16,17 of the bucket attachment means. This sliding movement produces apermanent wedge-force which results in increased abutment of the shaft23 against the hooks 4, 5 so that a permanent joint is obtained,entirely without clearance, this abutment force against the hooks 4, 5deriving from said wedge-forces transmitted via the counter members 16,17; 39.

Since the pressure from the link arms on the coupling means, initiatedby the tension pin 21, is allowed to pass through the stick shaft 23,the pivoting of the bucket about the operating arm stick is such thatthe forces from the stick are transmitted directly to the bucket via thestick shaft and the bucket coupling members (hooks 4, 5). The play-freejoint obtained according to the invention will be subject to very littlewear and such wear as does occur will not in any case give rise toclearance since it is automatically and immediately compensated by theinherent wedge-force so that the joint remains play-free. In otherwords, the joint is self adjusting.

The tension pin 21 provides effective mechanical locking which isachieved manually in the embodiment shown. However, if desired, thelocking may be achieved hydraulically or pneumatically.

The hooks can be welded directly onto the top of the bucket, as can alsothe locking shackle 11, wedge support 14 and counter members 16, 17, togive the least possible increase in the weight of the bucket.Alternatively at least the locking shackle 11, wedge support 14 andcounter members 16, 17 may be welded to a plate which is in turn weldedto the top of the bucket as a unit. If desired, the hooks may also bewelded to said plate.

The locking device can be designed in a variety of ways within the scopeof the invention. For instance, the central locking shackle may bereplaced by two locking eyes, each arranged in line with one of thecounter members 16, 17 and one of the hooks 4, 5 and having alignedopenings to receive a wedge-like tension pin. In this case the openingsof both locking eyes are provided with inclined support surfaces so asto cooperate with the tension pin which is then provided with two wedgesections the same distance apart as the locking eyes, the rear wedgesection being higher (larger cross-section) than the front wedgesection, and the openings in the locking eye similarly of the differentsize to enable the tension pin to be inserted in wedge position. Inorder to compensate for wear on the support surfaces, the supportsurfaces of the locking eyes may be effected on separate plates or thelike which can be adjusted by means of a screw.

As is seen, the design of the attachment means 20, 25 and their uniquefit to each other, causes no building height between operating arm andbucket, i.e. the pivot axis of the bucket on the operating arm is at thesame level it would be at if the operating arm were secured to thebucket in conventional manner, e.g. by an attachment lug, without theuse of a quick coupling.

The valuable effect achieved by eliminating the building height of thequick coupling, while at the same time making the coupling light, canalso be achieved by allowing the stick shaft to be in indirectengagement with the coupling device of the bucket (or other implement)in which case the pressure from the tension pin to the coupling devicewill still pass through the shaft 23. Such an embodiment is shown inFIGS. 11 and 12 wherein parts which substantially correspond to parts ofthe embodiment shown in FIGS. 1 to 6 at the same reference designations.The bucket attachment means include a coupling device in the form of twocoupling elements 60,61 located at predetermined distance from eachother, each having an aperture 62,63 facing the stick shaft 23. Thisaperture is conical so that an inner conical support surface is formed.The stick shaft 23 is here provided with an intermediate connectionmember in the form of two cylindrical sleeves 66, 67, each with aconical pin 68,69 corresponding to said apertures 62,63, forming conicalsupport surfaces 70,71. The pins can be turned on the shaft 23 by meansof the sleeves 66,67 in order to permit said pressure transmission viathe shaft, and facilitate their insertion into the apertures 62,63whereby the pins 68,69 are arranged to assume a coupling position inwhich they protrude in a direction away from the operating cylindershaft 24. The pins form a right-angle with the stick shaft 23 and, dueto the sleeves 66,67, have a centre of pivot coinciding with the shaftcentre. In said coupling position the centre line of the pins 68,69should preferably coincide with a centre plane C₁ -C₂ through the centreof the shafts. As with the embodiments described above, the lockingdevice is arranged to exert a pressure on the link arms 26,27, thuspressing the stick shaft 23 against the coupling elements 60,61 viatheir ends to produce a permanent play-free joint. According to analternative embodiment the coupling device is in the form of two hooks,as described earlier, whereas the stick shaft has an intermediateconnection member in the form of two cylindrical sleeves to cooperatewith the hooks.

FIGS. 8-10 show schematically another embodiment of the coupling meansaccording to the invention. The bucket 101 of an excavating machine isprovided on its upper side 102, facing away from the digging edge, withan attachment means 120 for a quick coupling according to the invention.This bucket attachment means comprises a coupling device in the form oftwo inwardly facing hooks 104, 105 spaced from each other, welded to thetop 102 of the bucket at the front edge 106 of its opening. The inwardlyfacing hooks are provided with function support surfaces 109, concave orsemi-cylindrical in shape, with predetermined radius for intimatecooperating with corresponding support surfaces on an attachment meansof the operating arm of the excavating machine, as will be describedbelow. The two support surfaces are aligned and perpendicular to theplane of symmetry S--S of the bucket.

The coupling means is provided with a locking device comprising twolocking eyes 180, 181 with aligned openings 182, 183 to receive wedgedtension pins 184, 185 in the form of pressure rods in a double-operatinghydraulic cylinder 190. The openings of the locking eyes have inclinedsupport surfaces in order to cooperate with corresponding inclinedsurfaces in the tension pins in wedge-like manner. The bucket attachmentmeans is also provided with two shoulder-like counter members 116, 117welded to the top 102 and located between the locking eyes 180, 181 andhooks 104, 105, in the vicinity of the former. Each of the countermembers 116, 117 has a plane functional support surface 118, 119 lyingin the same plane and inclined inwardly in the direction of the hooks104, 105 to cooperate with corresponding surfaces of the operating armattachment means as will be described below.

As described earlier, the operating arm of the excavating machineincludes a stick (not shown) and a hydraulic operating cylinder (notshown) arranged on its front side (facing away from the excavatingmachine). At its free end the stick is provided with a horizontal pin orshaft 123 on which the bucket 101 pivots. The shaft 123 thus forms thepivot centre of the bucket while said hydraulic cylinder, eitherdirectly or indirectly via links, is provided with a horizontal pin orshaft 124 which is parallel to the stick shaft 123 and thus located infront of this and indirectly connected to the bucket 101 to obtain acontrolled swinging movement of the bucket about the centre of the shaft123.

Said shafts 123, 124 form parts of an attachment means 125 on theoperating arm, this attachment means also including a link means in theform of two parallel link arms 126, 127, each provided with a lockingend portion 186 and a coupling end portion 187. At the locking endportion 186 of each link arm, at a predetermined distance from thecoupling end portion 187, are shaft support means in the form of acylindrical sleeve with a horizontal aperture to receive the shaft 124and an abutment portion 136 exerting leverage, which protrudes from thesleeve 131 in backward direction from the shaft 124, i.e. in a backwardextension of the link arm, forming an obtuse angle with the waist ormain part 137 of the link arm located between the shafts 123, 124. Onits upper side, facing away from the bucket, the abutment portion isprovided with a functional, flat surface 138 arranged to cooperate witha corresponding support surface of the tension pin 184, 185,respectively. The hydraulic cylinder 190 is supported by the link arms126, 127 by means of a rod or the like, the free ends of which restfreely with clearance in sleeves (FIG. 8). The rod is thus notpermanently joined to the link arms and these can therefore move freelyin the event of strain between bucket and operating arm. The hydrauliccylinder can thus still be considered to constitute a part of thelocking device for the implement attachment means.

Furthermore, each link arm is provided with a counter member 139 withinits locking end portion, designed with a functional, flat supportsurface 140, designed to abut said functional support surfaces 118, 119of the counter members 116, 117 of the bucket attachment means,cooperating to produce a wedge effect. These functional support surfaces118, 119 and 140 incline towards the hooks 104, 105 with the sameinclination. The inclination is such that an extension of the supportsurfaces forms an acute angle with the abutment portion support surfaces138, this angle having the values specified for the first embodimentdescribed. The support surfaces 118, 119 and 140 are preferably inclinedso that their extensions form an acute angle with a centre planeextending through the centres of the shafts 123, 124, said angle havingthe values specified for the first embodiment described. The countermember 139 is arranged immediately below the sleeves 131.

Each link arm 126, 127 is also provided at its coupling end portion witha shaft support means in the form of a sleeve 188 having a horizontalaperture to receive the shaft 123. Said shaft support member may bearranged with or without pivoting of the shaft (i.e. as shaft bearingmeans or not) and may include bushings. The sleeve is preferablycylindrical and provided externally with a functional concave orsemi-cylindrical support surface 189 extending transversely or axially(in relation to the shaft 123) and having a predetermined radiuscorresponding to the radius of the semi-circular support surfaces 109 ofthe hooks 104, 105, so that maximum contact is obtained between thesesurfaces. The support surfaces of the hooks preferably encompass thegreatest possible sector angle, i.e. 180°, as can be seen in FIG. 10.The support surface 189 of the sleeve 188 is thus immediately outsidethe shaft 123 as close as the wall thickness of the sleeve permits,suitably about 15 mm. The support surface 189 is also located in linewith and on both sides (symmetrically) of the centre plane through thecentres C₁, C₂ of the shafts 123, 124 and on the side of the shaft 123facing away from the link arms.

In the embodiment according to FIGS. 8 to 10, the force from the tensionpins 184, 185 is transmitted to the hooks 104, 105 via counter members139, shaft 124, link arms 126, 127 and their sleeves 188 abuttingdirectly against the hooks. The shaft 123 is thus not affected by thispressure load. Thus, when stresses occur due to the movement of thebucket with the aid of the operating arm, pressure forces occurexternally on the sleeves 188, i.e. on the support surfaces 189, towardsor away from the support surface 109 of the hooks and on the inside ofthe sleeves towards or away from the shaft 123. The joint is entirelyplay-free at the support surfaces 109 of the hooks.

In order to facilitate insertion of the transverse sleeves 188 in thehooks, the former are provided with a conical ring 191, the conicalsurface 192 serving as a guide surface. The described embodiment of theoperating arm attachment means permits simple modification for severaldifferent types of excavating machines and the bucket is provided withan attachment means which fits all these modifications. Themodifications are due to variations in the stick width in differenttypes of excavating machines and entail the distance between the sleeveson shaft 123 being adjusted to correspond to the stick width. In someembodiments the rings are removed. The common bucket attachment means isadjusted for these modifications by merely extending the counter members116, 117 towards or away from each other, thus permitting differentpositions are possible on the abutment portions at the sleeves 131.

The cooperating arc-shaped support surfaces of the shaft support sleeves188 and hooks 104, 105 enable the bucket to be pivoted before thelocking device has been applied during assembly.

FIG. 13 shows schematically an embodiment of an operating arm attachmentmeans 125 similar to that shown in FIGS. 8 and 10 with the exceptionthat the guide means on each link arm is in the form of a circular arcmember 191a thus being a part of the conical ring 191 shown in FIGS. 8and 10. The circular arc member 191a has an inclined guide surface 192ain relation to the coupling device and is arranged to cooperate with thecoupling device to facilitate connecting of the operating arm attachmentmeans to the coupling device. FIG. 13 also shows the lower part of theoperating arm of the excavating machine. The operating arm comprises astick 200 and a hydraulic operating cylinder 201 arranged on the frontof the stick 200. The stick 200 is provided at its free end with saidpin or shaft 123 pivotably carrying the bucket and thus forming thecentre of oscillation of the bucket. The hydraulic cylinder 201 isindirectly via links 202 provided with said horizontally arranged pin orshaft 124 which is parallel to the stick shaft 123. The links 202 arepivotable on horizontal pin 203. Links 204 are pivotable on said pin 203to connect the hydraulic cylinder 201 to the stick 200 via a horizontalpin 205.

As can be seen from the embodiments shown in the drawings, the couplingdevices 4, 5; 104, 105, seen in assembly position, are arranged in astraight line with the shafts 23, 24; 123, 124 so that they areintersected by the centre plane C₁ -C₂ coinciding with the shaft centresand consequently also passing through the shaft support means of thestick shaft. Such an arrangement, beneficial in many respects, combinedwith link arms has not been used previously in quick couplings forimplements of this type. In both the shown embodiments the centre lineC₂ of the stick shaft coincides with that of the radius of thesemi-cylindrical support surfaces of the hooks. The link arms are thusunloaded since the forces from bucket to stick and vice versa aretransmitted by the shortest route. The constantly occurring strokes arenot therefore transmitted further through the link arms. These are thusnot damaged and can be made light. The link arms may preferably be bentupwards, following the dome-shape of the bucket, thus enabling thedesired dome to be retained. The embodiment of the operating armattachment means shown in FIGS. 8 and 10 can be used, if desired, tobring the stick shaft into direct engagement with the hooks on thebucket. In this case, corresponding minor adjustments are made on thelink arms and their shaft support means so that they and the stick leaveparts of the shaft free for engagement with the hooks. A couplingaccording to the present invention has the following advantages: (a) Ithas extremely low weight (about 30 kgs for a machine up to 14 tons) andtherefore saves material, as well as being light to use and assemble.(b) The construction is simple, making it quick and easy to fit thebucket to the excavating machine. (c) It has no intermediate piece whichwould cause building height and increased weight. (d) The low weightdoes not necessitate altering the bucket volume. (e) It enables theforce-absorbing dome of the bucket to be retained, thanks to the linkarm construction, since the link arms may be arc-shaped to suite thedome. (f) It entails improved, even optimum conditions for the forcetransmission between bucket and operating arm and the link arms are notaffected to any noticeable extent since the forces are transmitteddirectly to the hooks from the stick and vice versa via the stick shaftand sleeve, if used, abutting the hooks. (g) Thanks to its design andimproved force transmission, the stipulated geometry of the bucket canbe retained. (h) It withstands diagonal breaking movements of the bucketsince the link arms make the coupling resilient, there being no rigid,stiffening joint between them and they can therefore move freely up anddown at their end portions at the four contact points with the bucket,independently and in relation to each other. They will therefore followthe diagonal breaking movements from the bucket when this is temporarilydeformed and becomes distorted by lateral stresses. (i) It maintains aplay-free joint between implement and operating arm at the contactpoints between operating arm attachment means and hooks even when thelink arms follow the diagonal breaking movements of the bucket. (j) Itis self-adjusting with respect to any slight wear which may occur at thecontact surfaces, and a play-free joint is thus always guaranteed. (k)According to a preferred embodiment, it can easily be modified to fitmany different types of excavating machines.

What I claim is:
 1. A coupling means for detachably coupling a workingimplement to an excavating machine operating arm having a stick and andan operating cylinder, said implement having an upper surface facing theoperating arm, with a front edge facing the excavating machine, saidcoupling means comprising an operating arm attachment means supported bythe operating-arm stick and operating cylinder and comprising a stickshaft journalled horizontally at the stick, and also a cylinder shafthorizontally journalled to the operating cylinder, said shafts beingparallel and spaced a predetermined distance from each other, saidcoupling means also comprising an implement supported attachment meansand comprising a coupling device and a locking device, by means of whichcoupling and locking devices the implement supported attachment means isarranged to be detachably coupled to the operating arm attachment means,said operating arm attachment means comprising link means in the form oftwo link arms, each mounted for independent movement relative to theother, one of the link arms being journalled by shaft supports includedin the link arm to one of the, same facing, ends of said shafts and theother link arm being independently journalled by its shaft supports toopposite ends of said shafts to define an operating arm attachment meansdevoid of additional bracing, each link arm having a free abutmentportion protruding as an extension of the link arms in backwarddirection from the operating cylinder shaft on the side of the operatingcylinder shaft facing away from the stick shaft, said link arms andimplement supported attachment means comprising counter members havingmating surfaces downwardly inclined toward said coupling device, saidcounter members cooperating with each other under pressure, said lockingdevice in operation exerting pressure on the abutment portions of thelink arms to move the link arms in the direction of the coupling deviceby virtue of the pressure in turn applied to the mating downwardlyinclined surfaces during said pressure application on the abutmentportions thereby to press the operating arm attachment means against thecoupling device to produce a permanent, play-free joint between saidimplement and operating arm.
 2. A means according to claim 1 whereinsaid attachment means of the operating arm is arranged to be pressedagainst said coupling device by means of said link arms which are thusin direct contact with the coupling device.
 3. A means according toclaim 1 wherein said attachment means of the operating arm is arrangedto be pressed against the coupling device by means of said stick shaft,which is thus in direct contact with the coupling device.
 4. A meansaccording to claim 1 wherein said attachment means of the operating armis arranged to be pressed against the coupling device by means of anintermediate connection supported on the stick shaft, which is thus indirect contact with said coupling device and is free from rigidconnection with the link arms.
 5. A means according to claim 2 whereinsaid link arms are provided at the ends facing away from the abutmentportions with free external support surfaces of predetermined shape,said coupling device being provided with free support surfaces of thesame predetermined shape as the free support surfaces of the link armsfor intimate cooperation therewith, whereupon the pressure exerted bythe locking device is propagated through the link arms and transmittedto the coupling device via said free support surfaces, the distance fortransmission of forces generated between implement and operating arm viathe stick shaft and the coupling device of the implement being limitedto a minimum equivalent to the wall thickness at said free externalsupport surfaces, measured between these support surfaces and theopposing inner surface abutting the stick shaft.
 6. A means according toclaim 2 wherein said support surfaces of the link arms and the couplingdevice are arc-shaped and have the same radius, and wherein the centreof the stick shaft and the centre of the coupling device support surfacecoincide.
 7. A means according to claim 6, wherein said coupling deviceconsists of two hooks spaced a predetermined distance from each other,with openings facing the upper surface of the implement, and wherein theshaft support comprises two cylindrical sleeves arranged at the samedistance from each other as the distance between the hooks and havingsaid free external support surfaces of the link arms.
 8. A meansaccording to claim 3 wherein each link arm is journalled on the shaft bymeans of a mounting plate provided with a hole and located adjacent toan end of the stick shaft, and is provided with an arc-shaped countermember which by means of a concave support surface abuts directlyagainst the shaft which is thus pressed against the coupling device, thehole in the mounting plate being sufficiently large in relation to thediameter of the stick shaft ends to permit this transmission of pressureto the coupling device via the counter member and the shaft.
 9. A meansaccording to claim 8 wherein said shaft and support surfaces of thecoupling device are arc-shaped and have the same radius and wherein thecenter of the shaft and the centre of the support surfaces of thecoupling device coincide.
 10. A means according to claim 9 wherein saidcoupling device consists of two hooks spaced a predetermined distancefrom each other, the hook openings facing the upper surface of theimplement.
 11. A means according to claim 2 wherein said counter membersof the link arms are arranged below and in the vicinity of the operatingcylinder shaft.
 12. A means according to claim 4, wherein said couplingdevice consists of two coupling elements spaced a predetermined distancefrom each other, each provided with an aperture having support surfacesfacing the stick shaft and wherein the stick shaft is provided with theintermediate connection means in the form of two pins protrudingperpendicularly from the stick shaft, said pins being arranged to assumea coupling position protruding in a direction away from the operatingcylinder shaft, the stick shaft thus being brought into indirectengagement with the coupling device by means of said pins, the pinsbeing in engagement with the apertures of the coupling elements.
 13. Ameans according to claim 2 wherein said locking device comprises one ormore tension pins arranged to effect said clamping by means of a wedgeeffect against the free abutment portions of the link arms.
 14. A meansaccording to claim 2 wherein said counter members are provided withsupport surfaces which in extended plane form an acute angle of about35°-85° with the support surfaces of the abutment portions, while thesupport surfaces of the counter members in extended plane form an acuteangle of from about 10° to about 65° to said centre plane.
 15. A meansaccording to claim 2 wherein a substantial part of the abutment portionsis arranged below a centre plane extending through the centres of theshafts.
 16. A means according to claim 5 wherein the front shaft supportof each link arm is provided with a guide means in the form of ringmeans having an inclined guide surface in relation to the respectivecoupling device, said guide means being arranged to cooperate with thecoupling devices to facilitate connecting of the operating armattachment means to the coupling device.
 17. A means according to claim11 wherein the link arms are vertically under the operating cylindershaft.
 18. A means according to claim 14 wherein the acute angle inextended plane of the support surfaces of the counter members with thesupport surfaces of the abutment portions is 50°-60°, while the acuteangle in extended plane of the support surfaces of the counter memberswith the center plane is 30°-60°.
 19. A means according to claim 18wherein the acute angle in extended plane of the support surfaces of thecounter members with the center plane is about 45°.
 20. A coupling meansfor detachably coupling a working implement to an excavating machineoperating arm having a stick and an operating cylinder, said implementhaving an upper surface facing the operating arm, with a front edgefacing the excavating machine, said coupling means comprising anoperating arm attachment means supported by the operating-arm stick andoperating cylinder and comprising a stick shaft journalled horizontallyat the stick, and also a cylinder shaft horizontally journalled to theoperating cylinder, said shafts being parallel and spaced apredetermined distance from each other, said coupling means alsocomprising an implement supported attachment means and comprising acoupling device and a locking device, by means of which coupling andlocking devices the implement supported attachment means is arranged tobe detachably coupled to the operating arm attachment means, saidoperating arm attachment means comprising link means in the form of twolink arms journalled at the ends of said shafts by means of shaftsupports included in the link arms, each link arm having a free abutmentportion protruding as an extension of the link arm in backward directionfrom the operating cylinder shaft on the side of the operating cylindershaft facing away from the stick shaft, said link arms and implementsupported attachment means comprising counter members cooperating witheach other under pressure, said locking device being arranged to exertpressure on the abutment portions of the link arms, thus moving the linkarms in the direction of the coupling device through wedge and levercooperation with said counter members and abutment portions and pressingthe operating arm attachment means against the coupling device toproduce a permanent, play-free joint between said implement andoperating arm, said attachment means of the operating arm being arrangedto be pressed against the coupling device by means of said stick shaft,which is thus in direct contact with the coupling device, each said linkarm being journalled on the stick shaft by means of a mounting plateprovided with a hole and located adjacent to an end of the stick shaft,each said link arm is provided with an arc-shaped counter member whichby means of a concave support surface abuts directly against the stickshaft which is thus pressed against the coupling device, the hole in themounting plate being sufficiently large in relation to the diameter ofthe stick shaft ends to permit this transmission of pressure to thecoupling device via the shaft.
 21. A means according to claim 20,wherein the stick shaft and support surfaces of the coupling device arearc-shaped and have the same radius and wherein the center of the stickshaft and the center of the support surfaces of the coupling devicecoincide.
 22. A means according to claim 21, wherein said couplingdevice consists of two hooks spaced a predetermined distance from eachother, the hook openings facing the upper surface of the implement. 23.A coupling means for detachably coupling a working implement to anexcavating machine operating arm having a stick and an operatingcylinder, said implement having an upper surface facing the operatingarm, with a front edge facing the excavating machine, said couplingmeans comprising an operating arm attachment means supported by theoperating arm stick and operating cylinder and comprising a stick shaftjournalled horizontally at the stick, and also a cylinder shafthorizontally journalled to the operating cylinder, said shafts beingparallel and spaced a predetermined distance from each other, saidcoupling means also comprising an implement supported attachment meansand comprising a coupling device and a locking device, by means of whichcoupling and locking devices the implement supported attachment means isarranged to be detachably coupled to the operating arm attachment means,said operating arm attachment means comprising link means in the form oftwo link arms journalled at the ends of said shafts by means of shaftsupports included in the link arms, each link arm having a free abutmentportion protruding as an extension of the link arm in backward directionfrom the operating cylinder shaft on the side of the operating cylindershaft facing away from the stick shaft, said link arms and implementsupported attachment means comprising counter members cooperating witheach other under pressure, said locking device being arranged to exertpressure on the abutment portions of the link arms, thus moving the linkarms in the direction of the coupling device through wedge and levercooperation with said counter members and abutment portions and pressingthe operating arm attachment means against the coupling device toproduce a permanent, play-free joint between said implement andoperating arm, said attachment means of the operating arm being arrangedto be pressed against the coupling device by means of an intermediateconnection supported on the stick shaft, which is thus in direct contactwith said coupling device and is free from rigid connection with thelink arms, said coupling device consisting of two coupling elementsspaced a predetermined distance from each other, each provided with anaperture having support surfaces facing the stick shaft and wherein thestick shaft is provided with the intermediate connection means in theform of two pins protruding perpendicularly from the stick shaft, saidpins being arranged to assume a coupling position protruding in adirection away from the operating cylinder shaft, the stick shaft thusbeing brought into indirect engagement with the coupling device by meansof said pins, the pins being in engagement with the aperture of thecoupling elements.
 24. A coupling means for detachably coupling aworking implement to an excavating machine operating arm having a stickand an operating cylinder, said coupling means comprising an operatingarm supported attachment means and an implement supported attachmentmeans, said operating arm supported attachment means comprising a stickshaft and a cylinder shaft respectively horizontally journalled to thestick and the operating cylinder of the operating arm, said stick andcylinder shafts being parallel and spaced a predetermined distance fromeach other, said implement supported attachment means comprising acoupling device and a locking device enabling detachable connection ofthe working implement to the operating arm via its attachment means, theoperating arm attachment means including link means comprising two linkarms each independently journalled at the ends of said stick andcylinder shafts by shaft supports on the link arms, each link arm havingan abutment end portion extending beyond the cylinder shaft in adirection away from the stick shaft and said locking device includingpin means proximate to said abutment end portion of said link arms, saidpin means having an inclined surface engageable with a correspondinglyinclined surface, defined by aperture means fixed to the implement, onforcing said pin means through the aperture of said aperture means, saidlink means and said implement supported attachment means further havingcooperating counter members having mating surfaces downwardly inclinedin a direction toward said stick shaft, said operating arm attachmentmeans, on mounting to said coupling device, having its counter membersurface in engagement with the surface of the counter member on theimplement supported attachment means, said pin means on being forcedthrough said aperture means fixed to the implement exerting a forceagainst said abutment end portion of said link arms thereby forcing thecounter member on said operating arm attachment means to move downwardlyrelative to the counter member on the implement and thereby alsoforwardly to firmly press the operating arm attachment means against thecoupling device to produce a positive connection between said implementand said operating arm.